In my view, questions of "importance" cannot be answered without first specifying "criteria of importance," of "important with respect to what."
Thus, I would give the following answer to your question:
"One criterion for "most important" is that which has most profoundly altered patterns of human mating. Changes in mating can affect the subsequent evolutionary course of the entire species, with cascading consequences for virtually every aspect of human life. Although many inventions have altered human mating over the past 2,000 years, television must rank among the most important. Television has changed status and prestige criteria, created instant celebrities, hastened the downfall of leaders, increased the importance of physical appearance, and accelerated the intensity of intrasexual mate competition — all of which have acutely transformed the nature of sexuality and mating and perhaps forever altered the evolutionary course of our species."